David Heinemeier Hansson and Porsche Napleton Racing (PNR) finished sixth in their debut race in the IMSA GT3 Cup Challenge by Yokohama on a Saint Patrick’s Day Thursday at Sebring International Raceway in the No. 37 PNR/37signals Porsche GT3.

“I feel great,” Hansson said. “I felt like I raced pretty much as hard as I could and the guys in front were fast. I am just happy I kept my car together all the way to the end. There were some good slides, but nothing too bad, and in the end it really did come down to tires.”

Hansson had a good start and settled into a quick but steady pace in eighth before making his first pass for position less than 10 minutes into the race to move to seventh place. He momentarily fell back to eighth at the 30 minute mark but had enough left in his PNR/37signals Porsche and Yokohama tires to have some fight for the finish.

“It seems like you are actually in there for a good hour-and-a-half to two hours,” Hansson said of the 45-minute race. “I was asking for time after 20 minutes, the car is just intense to drive. You have got to back off when you are halfway through it because the tires get real greasy and if you keep on pushing, you are going to find a flat spot. And once you find a flat spot, you’re toast.”

Flat spots actually factored into Hansson’s last lap move. After getting back to seventh, Hansson reeled in the sixth place Porsche and was right on its rear bumper as the white flag flew.

“I could see on his car that he had a flat spot too, I had a flat spot, so I was just trying to push him and see if I could get him to make a mistake going deep,” Hansson said. “In turn 10 I guess his left front just gave up and he went straight off the track.”

Thursday’s race was the first of this week’s pair of sprints at Sebring that kick off the 2011 IMSA Porsche GT3 Cup season. Tomorrow’s race is scheduled to start at 4:20 p.m. and Hansson plans to put to good use some of things he learned in today’s successful debut run.

“For me I have just got to back it off a little more I think,” Hansson said. “I don’t think I lost too much time not pressing 120%.”- PNR